1. Field of the Invention
The invention refers to a device for attaching a protective insulation material to the end of an electrical wire having at least one lead, with a contact element attached to the bare end of the lead. The device includes an injection molding unit, through which the protective cover is extruded around the contact element and the end of the wire. The part of an electric connector thus made may be a plug or an outlet. The contact elements on the conductor of the wire are pins or sockets. Wires, to which a plug or a socket is permanently attached at one end, are described as "premanufactured" wires. The other end of such wires generally remains free. The wires are delivered to the end user as semi-finished products, for installation in any electrical device. This requires the desired part of the electric connector to be extruded onto the wire, and the other end of the wire to be prepared for connection to the electrical device without any additional expenditure. However, such premanufactured wires can have electric connector parts attached at both ends.
2. Description of the Prior Art
German Patent Document No. DE-PS 24 40 264 describes a process for producing premanufactured wires. This process is fully automatic, up to the attachment of contact elements to the bare lead of the wire. However, while this document mentions that the protective cover can be automatically extruded, no information is provided regarding the configuration of a corresponding device. In addition, provisions are made to extrude protective covers to the wire ends with contact elements, with existing injection equipment requires the wire ends to be manually inserted one by one, or several at a time. Thus, the cost of producing a premanufactured wire using this equipment is considerable.
With the device according to German Patent Document No. DE-OS 37 20 041, premanufactured wires can be produced automatically by cyclic advance. One end of a wire equipped with contact elements is cyclically advanced to at least two injection molding devices, hereinafter simply called "extruders". Each extruder extrudes a part of the protective cover to be produced. The amount of material for each part is measured, so that each part hardens sufficiently during the cycle time, and can be further transported without damage. Although this device is able to produce a premanufactured wire in one operation, the cost is relatively high, since each part requires its own extruder. In addition, the part must be extruded with great care, to ensure that a homogeneous protective cover is produced.